<?php
$var = 300;

$int_options = array (
		"options" => array (
				"min_range" => 0,
				"max_range" => 256 
		) 
);

if (! filter_var ( $var, FILTER_VALIDATE_INT, $int_options )) {
	echo ("Integer is not valid");
} else {
	echo ("Integer is valid");
}
?>